/* ─── 黑白机能风 / Monochrome Techwear ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0a0a0a;
  --bg2: #111;
  --bg3: #1a1a1a;
  --border: #2a2a2a;
  --text: #ccc;
  --text-dim: #666;
  --text-bright: #fff;
  --accent: #888;
  --danger: #a44;
  --success: #6a6;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: 'Consolas', 'Monaco', 'Menlo', 'Courier New', monospace;
  font-size: 14px;
  line-height: 1.5;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ─── 扫描线 ─── */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(0,0,0,0.08) 2px,
    rgba(0,0,0,0.08) 4px
  );
  pointer-events: none;
  z-index: 9999;
}

/* ─── 滚动条 ─── */
::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent); }

/* ─── 布局容器 ─── */
#app {
  display: flex;
  height: 100vh;
  width: 100vw;
}

/* ─── 侧边栏 (大厅) ─── */
#sidebar {
  width: 280px;
  min-width: 280px;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  z-index: 10;
}

#sidebar-header {
  padding: 16px;
  border-bottom: 1px solid var(--border);
  text-align: center;
}

#sidebar-header h1 {
  font-size: 16px;
  font-weight: 400;
  color: var(--text-bright);
  letter-spacing: 4px;
  text-transform: uppercase;
}

#sidebar-header .subtitle {
  font-size: 10px;
  color: var(--text-dim);
  letter-spacing: 2px;
  margin-top: 4px;
}

/* ─── 连接状态 ─── */
#conn-status {
  padding: 6px 16px;
  font-size: 11px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 6px;
}

#conn-status .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--danger);
}

#conn-status .dot.online { background: var(--success); }

/* ─── 操作按钮 ─── */
#sidebar-actions {
  padding: 12px 16px;
  display: flex;
  gap: 8px;
  border-bottom: 1px solid var(--border);
}

.btn {
  flex: 1;
  padding: 8px 12px;
  background: var(--bg3);
  color: var(--text);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.15s;
  text-align: center;
}

.btn:hover {
  background: var(--border);
  color: var(--text-bright);
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  border-color: var(--accent);
  color: var(--text-bright);
}

/* ─── 房间列表 ─── */
#room-list {
  flex: 1;
  overflow-y: auto;
  padding: 8px 0;
}

.room-item {
  padding: 10px 16px;
  cursor: pointer;
  border-bottom: 1px solid var(--border);
  transition: background 0.1s;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.room-item:hover {
  background: var(--bg3);
}

.room-item .room-name {
  font-size: 13px;
  color: var(--text);
}

.room-item .room-meta {
  font-size: 10px;
  color: var(--text-dim);
}

.room-item .online-count {
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 2px 6px;
  font-size: 10px;
  color: var(--text-dim);
}

#room-empty {
  padding: 40px 16px;
  text-align: center;
  color: var(--text-dim);
  font-size: 12px;
}

/* ─── 聊天区域 ─── */
#chat-area {
  flex: 1;
  display: none;
  flex-direction: column;
  background: var(--bg);
}

#chat-area.active {
  display: flex;
}

/* 聊天头部 */
#chat-header {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg2);
}

#back-btn {
  display: none;
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 4px 10px;
  font-family: inherit;
  font-size: 12px;
  cursor: pointer;
}

#back-btn:hover { color: var(--text-bright); }

#chat-room-name {
  font-size: 14px;
  color: var(--text-bright);
  letter-spacing: 2px;
}

#chat-online {
  margin-left: auto;
  font-size: 11px;
  color: var(--text-dim);
}

#delete-room-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: 3px 8px;
  font-family: inherit;
  font-size: 10px;
  cursor: pointer;
  transition: all 0.15s;
  letter-spacing: 1px;
  margin-left: 8px;
}

#delete-room-btn:hover {
  border-color: var(--danger);
  color: var(--danger);
}

/* 消息区域 */
#messages {
  flex: 1;
  overflow-y: auto;
  padding: 12px 16px;
}

.msg {
  margin-bottom: 6px;
  padding: 4px 0;
  word-wrap: break-word;
  animation: fadeIn 0.15s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.msg .msg-time {
  color: var(--text-dim);
  font-size: 11px;
  margin-right: 8px;
}

.msg .msg-user {
  color: var(--text-bright);
  font-size: 12px;
  margin-right: 8px;
}

.msg .msg-user::after {
  content: '>';
  margin-left: 4px;
  color: var(--text-dim);
}

.msg .msg-text {
  color: var(--text);
  font-size: 13px;
}

/* 撤回按钮 */
.msg-recall {
  display: none;
  margin-left: 8px;
  font-size: 10px;
  color: var(--text-dim);
  cursor: pointer;
  opacity: 0.5;
  transition: opacity 0.15s, color 0.15s;
}

.msg:hover .msg-recall {
  display: inline;
}

.msg-recall:hover {
  opacity: 1;
  color: var(--danger);
}

.msg.system {
  padding: 2px 0;
}

.msg.system .msg-text {
  color: var(--text-dim);
  font-size: 11px;
  font-style: italic;
}

/* 输入区域 */
#input-area {
  padding: 12px 16px;
  border-top: 1px solid var(--border);
  background: var(--bg2);
  display: flex;
  gap: 8px;
}

#msg-input {
  flex: 1;
  padding: 10px 12px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 13px;
  outline: none;
  transition: border-color 0.15s;
}

#msg-input:focus {
  border-color: var(--accent);
}

#msg-input::placeholder {
  color: var(--text-dim);
}

#send-btn {
  padding: 10px 20px;
  background: var(--bg3);
  color: var(--text);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.15s;
  letter-spacing: 1px;
}

#send-btn:hover {
  background: var(--border);
  color: var(--text-bright);
}

/* ─── 无聊天占位 ─── */
#chat-placeholder {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-dim);
  font-size: 12px;
  letter-spacing: 2px;
}

/* ─── 弹窗 ─── */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  z-index: 100;
  align-items: center;
  justify-content: center;
}

.modal-overlay.active {
  display: flex;
}

.modal {
  background: var(--bg2);
  border: 1px solid var(--border);
  padding: 24px;
  width: 320px;
  max-width: 90vw;
}

.modal h2 {
  font-size: 14px;
  font-weight: 400;
  color: var(--text-bright);
  letter-spacing: 2px;
  margin-bottom: 16px;
  text-transform: uppercase;
}

.modal .field {
  margin-bottom: 12px;
}

.modal label {
  display: block;
  font-size: 11px;
  color: var(--text-dim);
  margin-bottom: 4px;
  letter-spacing: 1px;
}

.modal input {
  width: 100%;
  padding: 8px 10px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 13px;
  outline: none;
}

.modal input:focus {
  border-color: var(--accent);
}

.modal .modal-actions {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}

.modal .modal-actions .btn {
  flex: 1;
}

/* ─── 错误提示 ─── */
#error-toast {
  display: none;
  position: fixed;
  top: 16px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--danger);
  color: var(--text-bright);
  padding: 8px 20px;
  font-size: 12px;
  z-index: 200;
  border: 1px solid #c55;
  animation: toastIn 0.2s ease;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateX(-50%) translateY(-10px); }
  to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ─── 移动端适配 ─── */
@media (max-width: 640px) {
  #sidebar {
    position: fixed;
    inset: 0;
    width: 100%;
    min-width: unset;
    z-index: 20;
    transition: transform 0.2s;
  }

  #sidebar.hidden {
    transform: translateX(-100%);
  }

  #chat-area {
    position: fixed;
    inset: 0;
    z-index: 15;
  }

  #chat-placeholder {
    display: none;
  }

  #back-btn {
    display: block;
  }

  #chat-area.active {
    display: flex;
  }

  .modal { width: 90vw; }
}

/* ─── 登录界面 ─── */
#login-screen {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 500;
}

.login-box {
  text-align: center;
  width: 280px;
  max-width: 90vw;
}

.login-box h1 {
  font-size: 20px;
  font-weight: 400;
  color: var(--text-bright);
  letter-spacing: 6px;
  margin-bottom: 6px;
}

.login-box .subtitle {
  font-size: 10px;
  color: var(--text-dim);
  letter-spacing: 2px;
  margin-bottom: 32px;
}

.login-field {
  margin-bottom: 16px;
}

.login-field input {
  width: 100%;
  padding: 10px 12px;
  background: var(--bg2);
  color: var(--text);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 14px;
  text-align: center;
  outline: none;
  letter-spacing: 4px;
}

.login-field input:focus {
  border-color: var(--accent);
}

.login-btn {
  width: 100%;
  padding: 10px;
  letter-spacing: 4px;
}

#login-error {
  margin-top: 12px;
  font-size: 12px;
  color: var(--danger);
  min-height: 18px;
}

/* ─── 备案信息 ─── */
.beian {
  position: absolute;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 11px;
  color: var(--text-dim);
  white-space: nowrap;
}

.beian a {
  color: var(--text-dim);
  text-decoration: none;
  transition: color 0.15s;
}

.beian a:hover {
  color: var(--text);
}

.beian-sep {
  margin: 0 6px;
  opacity: 0.4;
}

/* ─── 危险按钮 ─── */
.btn-danger {
  border-color: var(--danger);
  color: var(--danger);
}

.btn-danger:hover {
  background: var(--danger);
  color: var(--text-bright);
}

/* ─── 弹窗警告文本 ─── */
.modal-warning {
  color: var(--danger);
  font-size: 11px;
  margin-bottom: 12px;
  line-height: 1.4;
}

/* ─── 移动端撤回按钮始终显示 ─── */
@media (max-width: 640px) {
  .msg-recall {
    display: inline;
  }
}